Motorcycle roadracing term used to describe a crash in which the bike is leaned over while cornering and flips back up towards the outside (i.e. the high side). A high side usually occurs when rear wheel traction is suddenly lost and the rider's panic causes him to abruptyl close (chop) the throttle. As a result, the rear wheel suddenly and forcefully regains traction, violently flipping the bike away from the direction of lean and throwing the rider skyward. Most racing injuries occur as a result of a high side since the rider has much further to fall.

The flip side of this (no pun intended) is a low side crash. These crashes are usually minor since the rider falls off much closer to the ground.

That clueless squid lost the rear halfway through Turn 7, chopped the throttle and high sided his brand new, chromed out R1 into the hay bales.

Old School Biker term for a crash where the bike and rider slide over the outer edge (highside) of a curve form losing traction due to wet or rough pavement, excessive speed, or, more than likely, simply showing one's ASS, drunk, stoned or sober!

Dumbfuck was drunk & stupid, showin' his ass when he highsided off Deadman's Curve!

A type of motorcycle crash wherein the rider is catapulted over the motorcycle as a result of the rear wheel losing traction, sliding out to one side, and then abruptly regaining traction while still out-of-line with the front wheel. Much more dangerous than a lowside.

Can be used as a noun or a verb:

Verb: "He was leading the race until he highsided coming out of the eighth turn."
Noun: "I've wrecked many times, but nothing is more terrifying than a highside."